1. Technical Field
The embodiments described herein relate to a semiconductor integrated circuit, particularly a data receiver of a semiconductor integrated circuit and a method for controlling the data receiver.
2. Related Art
A conventional data receiver of a semiconductor integrated circuit, as shown in FIG. 1, includes termination resistors R1_T, R2_T connected between a terminal of a power voltage VDD and a terminal of a ground voltage VSS, an amplifier 10, a delay chain 20, and a latch 30.
The amplifier 10 can amplify received data on the basis of a reference voltage VREF received from the outside and output the amplified signal “AMP_OUT”. The amplifier 10 can include a circuit for an equalization function. An equalization function is a technology for improving the operational margin of the data receiver that operates at a high speed by using past date to detect present data.
The amplifier 10 uses feedback data EQ− and EQ+ as past data. One of the feedback data, EQ− or EQ+, has the same logic value as the amplified signal “AMP_OUT” and the other feedback data has an opposite logic value. The delay chain 20 can delay and transmit the amplified signal “AMP_OUT” to the latch 30. The latch 30 can latch the amplified signal “AMP_OUT” based on the clock signal “CLK”.
A conventional data receiver of a semiconductor integrated circuit can use the equalization function. The amplified signal “AMP_OUT”, output from the amplifier 10, can be maintained at high impedance state High-Z by the termination resistors R1_T, R2_T in a period in which data is received. The high impedance state can have a level of (VDD−VSS)/2, i.e. an inaccurate logic level that may be recognized as a high level or a low level.
The high-impedance amplified signal “AMP_OUT”, having an inaccurate logic level in the period when data is not received, can be fed-back using the feedback data to the amplifier 10 through the delay chain 20. Accordingly, since the feedback data can have an inaccurate logic level in the period when data is not received, the amplifier 10 may not accurately detect data received after a high impedance level.